[slim] Re: How many streams at the same time ?
thank you for the discussion about the security margin. I am sure that we can exceed 80 mb/s on a switched environment but counting on a 50mb/s seems to be a safe limit ... which in fact is not a limit in this case I worry more about the ability of the server and of the hard drive to deliver 6 to 8 signals at the same time. Of course I assume that no transcoding will be done on the server side,. Did somebody tried this successfully already? -- Bee Bee's Profile: http://forums.slimdevices.com/member.php?userid=5794 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
[slim] Re: How many streams at the same time ?
Bee Wrote: thank you for the discussion about the security margin. I am sure that we can exceed 80 mb/s on a switched environment but counting on a 50mb/s seems to be a safe limit ... which in fact is not a limit in this case I worry more about the ability of the server and of the hard drive to deliver 6 to 8 signals at the same time. Of course I assume that no transcoding will be done on the server side,. Did somebody tried this successfully already? I've had about four or five playing at once with no problem on a 2.4GHz Pentium 4 running a 2.4 linux kernel. I've never had occasion to try to run more than that many players simultaneously. I think if you avoid transcoding you should be able to support a lot of players simultaneously. -- rudholm rudholm's Profile: http://forums.slimdevices.com/member.php?userid=2980 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
Re: [slim] Re: How many streams at the same time ?
I worry more about the ability of the server and of the hard drive to deliver 6 to 8 signals at the same time. 6-8 clients isn't a number you should worry about. I'm running five devices on a low-power Via C6/1000 with absolutely no problem at all. Sometimes I'm even using AlienBBC (only on one at a time, though). -- Michael --- Help translate SlimServer by using the StringEditor Plugin (http://www.herger.net/slim/) ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
[slim] Re: How many streams at the same time ?
Bee Wrote: thank you for the discussion about the security margin. I am sure that we can exceed 80 mb/s on a switched environment but counting on a 50mb/s seems to be a safe limit ... which in fact is not a limit in this case I worry more about the ability of the server and of the hard drive to deliver 6 to 8 signals at the same time. Of course I assume that no transcoding will be done on the server side,. Did somebody tried this successfully already? You don't have to worry about hard drive speed. See here: http://forums.slimdevices.com/showpost.php?p=98345postcount=11 A USB 2.0 drive is a few orders of magnitude faster than required and an internal drive should be even faster than that. Even a lowly USB 1.1 drive could handle several WAV streams. Only when you go back to 1998 and the days of USB 1.0 would you have problems with just one WAV stream. Server capacity is another matter, but anecdotal evidence suggests the practical limit for players is a dozen or so. Usually it's the network that will give out first. The server isn't working all that much harder as players are added. -- Mark Lanctot Mark Lanctot's Profile: http://forums.slimdevices.com/member.php?userid=2071 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
[slim] Re: How many streams at the same time ?
Mark Lanctot Wrote: Not to beat up on poor ceejay, but I tested this once for a review of a router: Well, fortunately I have quite a thick skin so don't feel terribly beaten up! The point I was trying to make in a very short post was that you probably won't get 100% usage from a LAN. I offered 50% as a rule of thumb that has worked well for me. I'd agree that a short point to point will get much closer to 100% because you really only have to worry about some overhead. But when you start to run long cables, or introduce multiple devices on the network, that figure drops. In my case, I know that if I'm doing a sustained long copy across my network (when backing up my music library, for example), 50% is pretty much what I get. Let's also not forget the context of the original question - how many streams can you have? Which implies multiple devices and contention as being relevant YMMV ! Ceejay -- ceejay ceejay's Profile: http://forums.slimdevices.com/member.php?userid=148 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
[slim] Re: How many streams at the same time ?
ceejay Wrote: Well, fortunately I have quite a thick skin so don't feel terribly beaten up! The point I was trying to make in a very short post was that you probably won't get 100% usage from a LAN. I offered 50% as a rule of thumb that has worked well for me. I'd agree that a short point to point will get much closer to 100% because you really only have to worry about some overhead. But when you start to run long cables, or introduce multiple devices on the network, that figure drops. In my case, I know that if I'm doing a sustained long copy across my network (when backing up my music library, for example), 50% is pretty much what I get. Let's also not forget the context of the original question - how many streams can you have? Which implies multiple devices and contention as being relevant YMMV ! Ceejay Multiple devices can drive down your aggregate bit rates when there are collisions but I wouldn't expect to see collisions in a switched environment. Neither would I expect to see long-ish cable runs costing much, unless you're pushing the rating limit (100M) or have out of spec cabling. If you're seeing 50Mb on your backups, you might have some other issue like bad cable/jacks or I/O limitations on your hosts. If your network is really bottlenecking you at 50Mb, something ain't right... -- rudholm rudholm's Profile: http://forums.slimdevices.com/member.php?userid=2980 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
[slim] Re: How many streams at the same time ?
Bee Wrote: can somebody give the rule for knowing the maximum of concurent streams with one server (Intel IMac for example) over a 100BT ethernet, with mp3 files (256kbps) ... or other configurations ? Well, at the top end: a 100Mbps LAN should give you about 50Mbps of usable throughput, so divide 50,000 by 256 to get 195 theoretical streams. Other bottle necks include the capacity of your hard disc to deliver bits (should be more than 50Mbps so not the limit) and the ability of your slimserver to keep up (which will probably be the limiting factor in practice - so depends on processor speed, system memory and other tasks running). This of course is assuming no transcoding on the server side. This is a long way of saying there is probably no magic formula which will tell you what you really want to know. Why not say how many you were thinking of, and see if anyone can offer evidence of matching that? There was also a thread a while ago on how many streams people had managed, and I seem to remember the answer was tens. HTH Ceejay -- ceejay ceejay's Profile: http://forums.slimdevices.com/member.php?userid=148 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
[slim] Re: How many streams at the same time ?
ceejay Wrote: Well, at the top end: a 100Mbps LAN should give you about 50Mbps of usable throughput, so divide 50,000 by 256 to get 195 theoretical streams. 50Mbps? I'm curious why you don't expect 100Mb/second from your 100Mb/second Ethernet. -- rudholm rudholm's Profile: http://forums.slimdevices.com/member.php?userid=2980 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
[slim] Re: How many streams at the same time ?
error correction and protocol overhead. You will *never* get 100mbit of through put on a 100mbit network. The speed quoted is the wire speed as opposed to the data transfer speed. Gigabit gets round this to some degree by using jumbo frames. Basically this means that your data to overhead ratio is better as each frame being sent contains more data. -- funkstar funkstar's Profile: http://forums.slimdevices.com/member.php?userid=2335 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
Re: [slim] Re: How many streams at the same time ?
rudholm wrote: ceejay Wrote: Well, at the top end: a 100Mbps LAN should give you about 50Mbps of usable throughput, so divide 50,000 by 256 to get 195 theoretical streams. 50Mbps? I'm curious why you don't expect 100Mb/second from your 100Mb/second Ethernet. Because Ethernet uses Carrier Sense Multiple Access with Collision Avoidance to control traffic. No Ethernet can deliver its rated speed, even getting 50% of its rated speed is hard if not impossible if there is any sharing of the network. And then you have to add overhead, addressing, error correcting, ack/nak messages, etc. For a practical example for Slim users, a WiFi 'b' network is rated as 11 megabits/second but it rarely can actually delivery uncompressed audio. This is a problem for SB1 users, since the SB1 only does WiFi B, and can't do Flac on the fly The RedBook specifies that stereo music is to be recorded in 16-bit PCM sampled at 44.1 kHz. A little arithmetic shows that the data stream of CD audio must be at least: Data Rate = X = 16 bits * 2 channels * 44.1kHz = 16 * 2 * 44100 = 1,411,200 bits/second = 176,400 bytes/second = 172 Kbytes/second So while Red Book (or uncompressed audio) is only 1.4 mb/s and that is only 12% or so of a WiFi b link speed, you can't get it. Assuming that you can get 10% of the rated speed is probably good engineering. -- Pat http://www.pfarrell.com/music/slimserver/slimsoftware.html ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
Re: [slim] Re: How many streams at the same time ?
On 6/4/06, Pat Farrell [EMAIL PROTECTED] wrote: Because Ethernet uses Carrier Sense Multiple Access with Collision Avoidance to control traffic. No Ethernet can deliver its rated speed, even getting 50% of its rated speed is hard if not impossible if there is any sharing of the network. And then you have to add overhead, addressing, error correcting, ack/nak messages, etc. Only hubbed Ethernet uses CSMA/CD; switched is full-duplex. I've benchmarked over 95 Mbps using generic consumer cards and switches, although that was card-to-card (netperf), not disk-to-disk. It's not that hard. - Jacob ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
Re: [slim] Re: How many streams at the same time ?
radish wrote: pfarrell Wrote: - again the myth that you can't run pcm to an sb1 is just that - a myth. I was doing it for a long time before I finally replaced my sb1 with a later model. Sure there was the odd glitch because that buffer was so small but in general it worked fine. My experience is different. I found PCM over wireless to my SB1 to be unlistenable, hence unusable. The fix was easy, drag an Ethernet cable. -- Pat http://www.pfarrell.com/music/slimserver/slimsoftware.html ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
[slim] Re: How many streams at the same time ?
With 802.11b or g, yeah, I'd be happy with 50% of advertised bitrates, but the topic at hand is 100Base-TX (i.e. wired) Ethernet. Even with the preamble byte, the SFD byte, the source and destination MAC addresses, the frame type, and the checksum, you're still only talking about about 20 bytes of overhead per frame, which isn't much even with 100Base-TX's MTU size of 1500 (i.e. not the jumbo frames that Gb Ethernet often uses). None of that could possibly account for a 1:2 ratio between user data and Layer 1 data. And my experience bears this out. I normally see about 10.5 megabytes per second transfer rates on 100Base-TX links, which is quite close to 100 megabits per second. So my question to ceejay stands --I'm curious why he expects only 50 megabits per second from 100Base-TX. -- rudholm rudholm's Profile: http://forums.slimdevices.com/member.php?userid=2980 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
[slim] Re: How many streams at the same time ?
Not to beat up on poor ceejay, but I tested this once for a review of a router: http://www.abxzone.com/forums/attachment.php?attachmentid=17528d=1107717661 See page 8. I found the 100 Mbps connection averaged 82.17 Mbps. Not quite 100 Mbps, but not 50 either. BTW that RacoonWorks Speed Test is a pretty cool little free program: http://www.snapfiles.com/get/speedtest.html You can test server - client on your internal network, wired or wireless, or between a web page and a local PC. -- Mark Lanctot Mark Lanctot's Profile: http://forums.slimdevices.com/member.php?userid=2071 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 ___ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
